diff --git a/chrome/content/zotero/overlay.xul b/chrome/content/zotero/overlay.xul
index 850e7756d4..9780cf93f2 100644
--- a/chrome/content/zotero/overlay.xul
+++ b/chrome/content/zotero/overlay.xul
@@ -97,7 +97,7 @@
 							<menuitem label="&zotero.toolbar.import.label;" oncommand="Zotero_File_Interface.importFile();"/>
 							<menuitem label="&zotero.toolbar.export.label;" oncommand="Zotero_File_Interface.exportFile();"/>
 							<menuseparator/>
-							<menuitem label="&zotero.toolbar.preferences.label;" oncommand="window.openDialog('chrome://zotero/content/preferences.xul','prefs','chrome,modal')"/>
+							<menuitem label="&zotero.toolbar.preferences.label;" oncommand="window.openDialog('chrome://zotero/content/preferences.xul','zotero-prefs','chrome,modal')"/>
 							<menuitem label="&zotero.toolbar.about.label;" oncommand="window.openDialog('chrome://zotero/content/about.xul','about','chrome,left=' + (window.screenX + 200) + ',top=' + (window.screenY + 100))"/>
 						</menupopup>
 					</toolbarbutton>
diff --git a/chrome/content/zotero/preferences.xul b/chrome/content/zotero/preferences.xul
index e1bd47136c..f6ae0b1b1d 100644
--- a/chrome/content/zotero/preferences.xul
+++ b/chrome/content/zotero/preferences.xul
@@ -26,7 +26,7 @@
 
 <!-- TODO: change to prefWindow? -->
 <dialog id="winMain" title="&zotero.preferences.title;" style="min-width:400px;"
-		onload="init();" ondialogaccept="accept()"
+		windowtype="zotero:pref" onload="init();" ondialogaccept="accept()"
 		xmlns="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">
 
 <script src="preferences.js"/>
@@ -45,7 +45,10 @@
 	<label value="&zotero.preferences.position.browser;"/>
 </hbox>
 
-<checkbox id="autoUpdateBox" label="&zotero.preferences.autoUpdate.label;"/>
+<hbox align="center">
+	<checkbox id="autoUpdateBox" label="&zotero.preferences.autoUpdate.label;"/>
+	<button id="updateButton" style="margin-top:0" label="&zotero.preferences.updateNow.label;" oncommand="Zotero.Schema.updateScrapersRemote(true)"/>
+</hbox>
 
 <checkbox id="reportTranslationFailure" label="&zotero.preferences.reportTranslationFailure.label;"/>
 
diff --git a/chrome/content/zotero/xpcom/schema.js b/chrome/content/zotero/xpcom/schema.js
index 39afa355c7..e09c9a6ed8 100644
--- a/chrome/content/zotero/xpcom/schema.js
+++ b/chrome/content/zotero/xpcom/schema.js
@@ -127,7 +127,15 @@ Zotero.Schema = new function(){
 			+ 'version=' + Zotero.version;
 		
 		Zotero.debug('Checking repository for updates (' + url + ')');
-		var get = Zotero.Utilities.HTTP.doGet(url, _updateScrapersRemoteCallback);
+			
+		if (force){
+			url += '&m=1';
+			var get = Zotero.Utilities.HTTP.doGet(url, _updateScrapersRemoteCallbackManual);
+		}
+		else {
+			var get = Zotero.Utilities.HTTP.doGet(url, _updateScrapersRemoteCallback);
+		}
+		
 		
 		// TODO: instead, add an observer to start and stop timer on online state change
 		if (!get){
@@ -388,7 +396,7 @@ Zotero.Schema = new function(){
 	/**
 	* Process the response from the repository
 	**/
-	function _updateScrapersRemoteCallback(xmlhttp){
+	function _updateScrapersRemoteCallback(xmlhttp, manual){
 		if (!xmlhttp.responseXML){
 			try {
 				if (xmlhttp.status>1000){
@@ -401,7 +409,10 @@ Zotero.Schema = new function(){
 			catch (e){
 				Zotero.debug('Repository cannot be contacted');
 			}
-			_setRepositoryTimer(ZOTERO_CONFIG['REPOSITORY_RETRY_INTERVAL']);
+			
+			if (!manual){
+				_setRepositoryTimer(ZOTERO_CONFIG['REPOSITORY_RETRY_INTERVAL']);
+			}
 			return false;
 		}
 		
@@ -415,15 +426,19 @@ Zotero.Schema = new function(){
 		// Store the timestamp provided by the server
 		_updateDBVersion('repository', currentTime);
 		
-		// And the local timestamp of the update time
-		var d = new Date();
-		_updateDBVersion('lastcheck', Math.round(d.getTime()/1000)); // JS uses ms
+		if (!manual){
+			// And the local timestamp of the update time
+			var d = new Date();
+			_updateDBVersion('lastcheck', Math.round(d.getTime()/1000)); // JS uses ms
+		}
 		
 		if (!translatorUpdates.length && !styleUpdates.length){
 			Zotero.debug('All translators and styles are up-to-date');
 			Zotero.DB.commitTransaction();
-			_setRepositoryTimer(ZOTERO_CONFIG['REPOSITORY_CHECK_INTERVAL']);
-			return false;
+			if (!manual){
+				_setRepositoryTimer(ZOTERO_CONFIG['REPOSITORY_CHECK_INTERVAL']);
+			}
+			return -1;
 		}
 		
 		try {
@@ -438,16 +453,46 @@ Zotero.Schema = new function(){
 		catch (e) {
 			Zotero.debug(e, 1);
 			Zotero.DB.rollbackTransaction();
-			_setRepositoryTimer(ZOTERO_CONFIG['REPOSITORY_RETRY_INTERVAL']);
+			if (!manual){
+				_setRepositoryTimer(ZOTERO_CONFIG['REPOSITORY_RETRY_INTERVAL']);
+			}
 			return false;
 		}
 		
 		Zotero.DB.commitTransaction();
-		_setRepositoryTimer(ZOTERO_CONFIG['REPOSITORY_CHECK_INTERVAL']);
+		if (!manual){
+			_setRepositoryTimer(ZOTERO_CONFIG['REPOSITORY_CHECK_INTERVAL']);
+		}
 		return true;
 	}
 	
 	
+	function _updateScrapersRemoteCallbackManual(xmlhttp){
+		var updated = _updateScrapersRemoteCallback(xmlhttp, true);
+		
+		// Update the "Update Now" button in the pref dialog with the result
+		var wm = Components.classes["@mozilla.org/appshell/window-mediator;1"]
+			.getService(Components.interfaces.nsIWindowMediator);
+		var enumerator = wm.getEnumerator('zotero:pref');
+		while (enumerator.hasMoreElements()){
+			var win = enumerator.getNext();
+			var button = win.window.document.getElementById('updateButton');
+			if (button){
+				if (updated===-1){
+					var label = Zotero.getString('zotero.preferences.update.upToDate');
+				}
+				else if (updated){
+					var label = Zotero.getString('zotero.preferences.update.updated');
+				}
+				else {
+					var label = Zotero.getString('zotero.preferences.update.error');
+				}
+				button.setAttribute('label', label);
+			}
+		}
+	}
+	
+	
 	/**
 	* Set the interval between repository queries
 	*
diff --git a/chrome/locale/en-US/zotero/preferences.dtd b/chrome/locale/en-US/zotero/preferences.dtd
index 505ad94e02..e8ccea9ffa 100644
--- a/chrome/locale/en-US/zotero/preferences.dtd
+++ b/chrome/locale/en-US/zotero/preferences.dtd
@@ -1,5 +1,6 @@
 <!ENTITY zotero.preferences.title		"Zotero Preferences">
 <!ENTITY zotero.preferences.autoUpdate.label		"Automatically check for updated scrapers">
+<!ENTITY zotero.preferences.updateNow.label		"Update now">
 <!ENTITY zotero.preferences.reportTranslationFailure.label	"Report broken site translators">
 <!ENTITY zotero.preferences.position.label			"Display Zotero">
 <!ENTITY zotero.preferences.position.above			"above">
diff --git a/chrome/locale/en-US/zotero/zotero.properties b/chrome/locale/en-US/zotero/zotero.properties
index 2c188a1919..ae3677129b 100644
--- a/chrome/locale/en-US/zotero/zotero.properties
+++ b/chrome/locale/en-US/zotero/zotero.properties
@@ -187,6 +187,9 @@ db.dbCorruptedNoBackup			= The Zotero database appears to have become corrupted,
 db.dbRestored					= The Zotero database appears to have become corrupted.\n\nYour data was restored from the last automatic backup made on %1$S at %2$S. The damaged file was saved in your Zotero directory.
 db.dbRestoreFailed				= The Zotero database appears to have become corrupted, and an attempt to restore from the last automatic backup failed.\n\nA new database file has been created. The damaged file was saved in your Zotero directory.
 
+zotero.preferences.update.updated = Updated
+zotero.preferences.update.upToDate = Up to date
+zotero.preferences.update.error = Error
 zotero.preferences.status.positionChange = Position change will take effect in new windows only
 
 fileInterface.itemsImported		= Importing items...